Gents, On Mon, May 11, 2009 at 10:54 AM, Dan White <dwhite@olp.net> wrote:
Andrey Gordon wrote:
[snip]
When I transfer a large file over FTP (or CIFS, or anything else), I'd expect it to max out either one or both T1, but instead utilization on the T1s is hoovering at 70% on both and sometimes MLPPP link utilization even drops below 50%. What am I'm not gettting here?
Sounds like the TCP window is either set 'small' or TCP window scaling either isn't enabled or isn't scaling to your bandwidth/delay product (for the hosts in question). Since FTP is a 'stream' based transport of file data (like http), you should see this scale to nearly all of or most of your links (assuming TCP isn't your issue). Additionally, when using CIFS, SMB, TFTP, NFS, and other command->acknowledgment style protocols over wide-area links (which aren't stream-based operations, but rather iterative operations on blocks or parts of a file), you likely will never observe a single transfer filling up the links. -Tk